Statistics on the health-related and economic costs of alcohol abuse were summarized in the application. We consider that the consequences of acute intoxication and of alcohol consumption by individuals with reduced acetaldehyde dehydrogenase 2 activity create especially severe damage to mitochondrial DNA that is not predictable based on low-dose exposures and has not been measured previously. Since this is an invasive study, we cannot use human tissues for this research, but will use wild-type and aldhZ'- mice. This knockout mouse strain provides a mode! for humans, mainly East Asians, with this enzyme deficiency. My collaborator, Dr. Shinya Shibutani, and I bring a considerable expertise in DNA damage and repair to the medically and socially important problem of alcohol-induced mitochondrial damage. The review of the original application noted that "the use of both acute and chronic EtOH exposure will likely yield valuable insights and the portions of the project relating to mtDNA damage (are) exciting and likely to bring clarity to the field." This comment provides an excellent summary of the end-product offered by our refocused research plan. We will provide the most comprehensive survey to date of the types of damage to mtDNA that are induced by excessive alcohol exposure. The study is designed to detect three important types of mtDNA damage that we consider have been overlooked by previous studies, namely lipid peroxidation damage, acetaldehyde adducts and protein-DNA cross-links. As part of our approach we will assess damage in nuclear DNA in the same tissue samples to test our hypothesis that the spectrum and abundance of DNA damage will differ in nuclear and mtDNA.